Many hunters and target shooters reload their own ammunition. During the reloading process, it is necessary to measure a precise weight of gun powder. Although many reloaders use scales or balances to measure an individual charge, it is desirable to employ an apparatus which will quickly and accurately provide a metered quantity of gun powder. Such devices are generally referred to as powder measure devices and typically comprise a drum having a transversely extending bore. A metering piston assembly is secured to the drum and a metering piston extends into the bore. Means are provided for varying the position of the piston within the bore whereby the volume of the bore is variable. The drum is generally received in a housing which includes a gun powder reservoir secured to the top thereof. When the drum is rotated so that the bore faces upwardly, the powder from the reservoir empties into the opened end of the bore. Upon rotation of the drum, the bore is moved such that its open end communicates with the discharge end of the powder measure device and, thereby, powder which fills the bore is discharged into a shell which is positioned beneath the device. Thereby, a metered quantity of powder is discharged from the device upon rotation of the drum.
Individuals who reload their ammunition will often reload both pistol ammunition and rifle or shotgun ammunition. Obviously, a larger quantity of gun powder is required with a shotgun or rifle shell as compared to a pistol shell. However, although the quantity of gun powder may vary depending upon the nature of the shell which is being reloaded, it is desired to maintain the same tolerances in either case. This requirement presents a problem for the following reasons. When a large quantity of gun powder is to be metered and discharged, the volume of the bore in the drum must obviously be large. In order to secure such a large volume, typically the diameter of the bore will be fairly large, for example approximately one inch. If one attempted to meter a small quantity of material by using a drum having a large diameter bore, it is clear that a small change in the position of the metering piston would represent a significant change in the volume of the bore. Thus, it is difficult to make small changes in the volume of a large diameter bore when attempting to meter a small quantity of material.
In the past, two approaches have been employed to overcome this problem. First, manufacturers have supplied powder measure devices with two separate drums, one having a large diameter bore with a large diameter piston and another drum having a small diameter bore with a small diameter piston. With this approach, a reloader would change measuring drums when going from a large size shell to a small size shell or vice-a-versa.
Another approach has utilized a single drum having two bores of different diameters and a metering piston positioned in each of the bores. With this arrangement, means were also provided for diverting the material from the reservoir to one of the two bores. A device of this type is shown in U.S. Pat. No. Des. 230,880 and is sold by Ohaus Scale Corporation of Florham Park, New Jersey under the designation Model No. 7200.
Although devices of the type described above have operated satisfactorily, it is evident that they necessarily require additional parts which may be used infrequently and which may be mislaid. For example, in the instance where a powder measure device is supplied with two drums, only one drum is used at one time. Thus, the other drum may be mislaid and is not used when the first drum is being operated. Similarly, with the Ohaus Powder Measure Device described above, the device includes two metering pistons and only one is used at any one time. Although each of the metering pistons in the Ohaus device is mounted in the drum and thereby will not be lost, the necessity of providing an additional metering piston increases the cost of the device. The object of this invention is to provide a powder measure device which does not employ anymore parts than are employed in single cavity powder measuring devices yet which has the capability of dual drum powder measure devices.